Tris-(polyalkoxyalkylated) isocyanurate compounds and their use as functional fluids

ABSTRACT

Novel tris-(polyalkoxyalkylated) isocyanurate compounds are described having the formula: ##STR1## wherein x is an integer from 2-10; Y is either a hydrogen or methyl group; and R is an alkyl group having from 1-4 carbon atoms. The use of these isocyanurate compounds as functional fluids, including hydraulic-type and heat transfer-type fluids, is also described. Such functional fluids have superior fire resistance properties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to novel isocyanurate compounds and their use infunctional fluid systems. More particularly, this invention relates tonovel tris-(polyalkoxyalkylated)isocyanurate compounds and their use infunctional fluid systems.

2. Description of the Prior Art

Tris-(substituted)isocyanurate compounds (i.e., isocyanurate estershaving the same substituents at each of three ring nitrogens) have beenwidely described in the literature. In particular, ethylene oxideadducts of isocyanurates, and mixtures thereof, as well as certaincarboxylic acid esters of the resulting polyols, have been described.For example, see U.S. Pat. No. 3,637,557, which issued to E. D. Littleon Jan. 25, 1972. The described isocyanurate compounds have been foundto be useful in a variety of applications, including functional fluidapplications.

Moreover, the prior art generally teaches that alkoxy alkyl chloridesmay be reacted with cyanuric acid in the presence of a base. See Col. 2,line 26 of U.S. Pat. No. 3,075,979. However, this teaching failed torecognize the possible utilization of such a reaction product asfunctional fluids. Furthermore, a literature article describes threespecific tris-(mono-alkoxyalkylated)isocyanurate compounds, i.e.,tris-(CH₃ OCH₂ CH₂)isocyanurate, tris-(C₂ H₅ OCH₂ CH₂)-isocyanurate andtris-(C₄ H₉ OCH₂ CH₂)isocyanurate. See Bull. Chem. Soc. Japan, Volume38, (10), pages 1586-1589 (1965). But such teachings do not describe orsuggest the novel tris-(polyalkoxyalkylated)isocyanurate compounds ofthe present invention nor describe their use as fire resistantfunctional fluids.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed attris-(polyalkoxyalkylated)isocyanurate compounds of the formula:##STR2## wherein x is an integer from 2-10; Y is either a hydrogen ormethyl group; and R is a lower alkyl group having from 1-4 carbon atoms.

This invention is also directed to the use of these isocyanuratecompounds as functional fluids, including hydraulic-type and heattransfer-type functional fluids. Such functional fluids have superiorfire resistance properties.

DETAILED DESCRIPTION

The compounds of Formula I may be prepared by first reacting one or morepolyglycol monoalkyl ethers with a chlorinating agent such as thionylchloride to produce the corresponding mono-chloro compounds. Thisreaction is represented by the following Equation A: ##STR3## where xcan vary from 2 to 10, preferably 2 to 5; Y can be hydrogen or methyl,preferably hydrogen; and R is lower alkyl having 1-4 carbon atoms,preferably a methyl group.

These mono-chloro compounds may be next reacted with trisodium cyanurateto form the instant compounds. This latter reaction is represented byEquation B: ##STR4##

One of the unexpected characteristics of the compounds of the presentinvention, as seen in Table I, below, is an increase in fire resistancewith increasing alkylene oxide content in the N-substituents. This isparticularly unexpected because alkylene oxide compounds, i.e., ethyleneoxide and propylene oxide, by themselves are highly flamable.

In the reaction illustrated by Equation A, polyglycol monoalkyl ethersare employed as a starting material. These polyglycol ethers arecommercially available from several sources. For example, polyglycolethers identified by the POLY-SOLV® trademark and sold by the OlinCorporation are one suitable source. It is intended that the presentinvention may employ both substantially pure polyglycol ethers andmixtures thereof. Preferably, the polyglycol portion of these compoundshas from 2 to 5 glycol groups, represented by having x in Equation Aequal from 2-5. Also, monoalkyl portion of this compound is preferably amethyl group. Specific preferred embodiments include diethylene glycolmonomethyl ether, triethylene glycol monomethyl ether, tetraethyleneglycol monomethyl ether and mixtures thereof.

Thionyl chloride (SOCl₂) is employed as the chlorinating agent inEquation A. This compound is a preferred chlorinating agent because ofits relatively low cost and the ease of its reacting with the polyglycolethers. However, other conventional chlorinating agents such as PCl₃,PCl₅ or POCl₃ may be alternatively employed, if desired.

This chlorination reaction illustrated by Equation A is a well knownreaction and may be carried out in any conventional manner. See ChemicalAbstracts Vol. 58, 450a, (1963), and Journal of American ChemicalSociety, Vol. 63, page 2279 et seq. (1941). For example, thechlorinating agent SOCl₂ may be added to the polyglycol monoalkyl etherin any standard reaction apparatus, preferably one with a gas scrubberto remove any gases generated during and after the reaction. Preferably,a 10-40% molar excess of the SOCl₂ over the polyglycol ether is employedto ensure the latter's substantially complete reaction. Furthermore, thereaction is preferably carried out at about ambient temperature (i.e.,from about 0° C. to about 30° C.) and at atmospheric pressure. Usually,the period for adding the SOCl₂ to the polyglycol ether is about 60minutes, followed by from about 15 minutes to 300 minutes of heatingtime in order to obtain a suitable yield of the desired monochloroproduct. Any inert solvent may be employed, although, preferably, nosolvent is needed. Any conventional recovery system for isolating thedesired chloropolyglycol monoalkyl ether may be employed. Usually, allof normal by-products (i.e., HCl and SO₂) are gaseous in nature and willbubble off during reaction, leaving the desired product in the reactor.If a substantially pure product is desired, purification by distillationmay be employed.

The reaction of the chloropolyglycol-monoalkyl ether and trisodiumcyanurate, as illustrated above by Equation (B), may be carried out inthe reaction apparatus employed for the chlorination reaction or inseparate conventional reaction apparatus. The trisodium cyanurate may beadded to the product of the prior reaction, or vice versa. Moreover,chemical equivalents to the trisodium cyanurate may be employed, ifdesired, to make the novel tris-(polyalkoxyalkylated)-isocyanuratecompounds of the present invention. Trisodium cyanurate is commerciallyavailable, or may be easily made by the neutralization of cyanuric acidby well-known methods.

This isocyanurate reaction illustrated by Equation (B) normally employsa chloropolyglycol monoalkyl ether to trisodium cyanurate molar ratio inthe range of about 2.5:1 to about 5:1, more preferably about 3:1 toensure good yields of the compounds of the present invention. Thereaction temperatures of this reaction usually are in the range of fromabout 100° C. to about 200° C., more preferably in the range of 120° C.to about 150° C. Furthermore, the reaction is most preferably carriedout at atmospheric pressure, although pressure in the range from 0.5atm. to 100 atm. may be used if desired. Such higher pressures areemployed if solvent is a lower boiling solvent. Preferably, the reactionis carried out in the presence of an aprotic polar solvent. Examples ofsuch suitable solvents include N,N-dimethylformamide (DMF),dimethylsulfoxide, hexamethylphosphorylamide and the like. DMF is themost preferred solvent. Preferably, such solvents are employed in arange from about 2:1 to about 10:1, more preferably, about 4:1 to about6:1, molar excess over the trisodium cyanurate. The time of the reactionusually includes about 30-120 minutes for adding the reactants together,preferably followed by a heating period from about 120 minutes to about1200 minutes, more preferably, from about 600 minutes to 720 minutes.

The products of the present invention can be recovered from the reactionmixture by any conventional method. Preferably, the by-product NaCl isfirst removed from the reaction mixture by conventional filtrationtechniques. Next, the solvent is then preferably removed by vacuumstripping. The remaining reaction mixture may be distilled byconventional methods such as molecular distillation to obtain a verypure product, if desired.

Of course, the novel tris-(N-polyalkoxyalkylated)-isocyanurate compoundsof the present invention may be made by other methods and the presentinvention is not intended to be limited to any specific method of makingthese compounds.

The isocyanurate compounds of the present invention have been found tobe particularly useful in functional fluid systems.

The functional fluid systems to which the present invention is directedincludes hydraulic-type functional fluid systems and heat transfer-typefunctional fluid systems.

The hydraulic-type fluid systems include any system wherein a mechanicaleffort is converted to pressure at a first location, the pressure istransmitted from this first location to a second location via ahydraulic fluid, and the pressure is converted to a second mechanicaleffort at the second location. Thus, the hydraulic systems contemplatedby the present invention include hydraulic brake systems, hydraulicsteering mechanisms, hydraulic transmissions, hydraulic jacks andhydraulic lifts, especially those that require a high degree of fireresistance. Included among these are the hydraulic systems used in heavyequipment and transportation vehicles including highway and constructionequipment, railways, planes and aquatic vehicles.

The heat transfer-type fluid systems include the hydraulic systemsdescribed above wherein heat is dissipated by the hydraulic fluid andinclude many other systems as well. In general, the present inventioncontemplates heat transfer systems wherein heat is passed from a firstheat conductor at a first location to a heat transfer fluid, the heat istransmitted from the first location to a second location via the heattransfer fluid, and the heat is passed from the heat transfer fluid to asecond conductor at the second location. Thus, the heat transfer systemsof the present invention include heat dissipation systems, fluidicheating systems, e.g., radiator-type circulating fluid heating systems,heating exchange systems such as gas-liquid and liquid-liquid concurrentand countercurrent tubular heat exchangers as are used, for example, inthe chemical process industries, cooling systems for nuclear reactors,radiator-type cooling systems, and any other temperature gradientsystems in which a closed or sealed fluid heat transfer medium is used.

In the functional fluid systems of the present invention, the compoundsof Formula I above are used in an effective amount. Thus, by aneffective amount of these compounds is meant the compound productwithout additional fluid components as well as fluids containingadditional fluid components. In one embodiment, the compounds of FormulaI may be employed without additives or diluents. Alternatively, thesecompounds may comprise the base component of a functional fluid or mayconstitute a minor component, e.g., an additive, in a functional fluidcontaining a different base component. In general, an effective amountmay be any amount which will produce the desired fluid characteristicsfor a given system. Therefore, as little as 5% or less of one or more ofthe compounds of Formula I may be used or as much as about 100% of thecompounds may be used, percentages by weight. Preferably about 20% toabout 95% of the functional fluid may be one or more of the compounds ofFormula I; more preferably, about 45% to about 90% of the fluid maycomprise one or more compounds of Formula I.

Various diluents, inhibitors and other additives are well known in thefunctional fluid art and these may optionally be added to the functionalfluids used in the systems of the present invention, if desired. Forexample, a diluent component may be one or more glycol monoethers ordiethers or formals of the formula:

    R.sub.1 [O--R.sub.2 ].sub.x OR.sub.3                       (II)

wherein R₁ is a lower alkyl of 1 to 4 carbon atoms; R₂ is alkylene of 1to 4 carbon atoms; R₃ is hydrogen or an alkyl of 1 to 4 carbon atoms;and x is an integer from 2 to 4. The R₁, R₂ and R₃ groups may bestraight chained or branched and the alkylene oxide group OR₂ in theabove formula may comprise mixtures of alkylene oxides. Also includedamong the possible diluents are one or more glycols, such as thealkylene glycols, having the formula:

    HO(R.sub.4 O).sub.y H                                      (III)

wherein R₄ is an alkylene of 2 to 3 carbon atoms and y is an integerfrom 1 to 5.

Illustrative of the above-described diluents are the following:diethylene glycol monoethyl ether, diethylene glycol monobutyl ether,triethylene glycol monomethyl ether, triethylene glycol monoethyl ether,tetraethylene glycol monomethyl ether, ethylene glycol, propyleneglycol, diethylene glycol and tetraethylene glycol and the various alkylethers of the above glycols. Various other diluents and mixturesthereof; for example, water, may also be used.

Generally, the particular amount of diluents which is used is notcritical and widely varying amounts may be used. More particularly, thediluent components may constitute from 0 up to about 80% by weight ofthe fluid and preferably from about 20 to about 60%.

Various additives may be added to the fluids used in the systems of thisinvention to control or modify various chemicals and physicalproperties. Among the various types of additives which can be added tothe fluids are included inhibitors for pH and corrosion control,antioxidants, rust inhibitors, viscosity index improvers, pour pointdepressants, lubricating additives, antifoamants, stabilizers, vaporphase corrosion inhibitors, rubber swelling adjusters, demulsifiers,dyes and odor suppressants. Generally, the total amount of additiveswhich may be incorporated into the fluid composition will vary betweenabout 0 to about 20%, e.g., from about 0.1 to 8% and more specificallyfrom about 0.2 to about 5% by weight based on the total weight of thefluid composition.

For example, alkaline inhibitors for pH and corrosion control mayoptionally be employed in an amount sufficient to maintain alkalineconditions in the fluid compositions, e.g., at an apparent pH value offrom about 7 to about 11.5, if desired. These inhibitors may generallybe added in an amount of from about 0 to about 8% by weight based on thetotal weight of fluid compositions, e.g., from about 0.5 to about 6%.Useful alkaline inhibitors include, for example, alkali metal salts ofhigher fatty acids such as potassium oleate, the potassium soap of rosinor tall oil fatty acids, amines such as morpholine and ethanolamine andamine salts such as mono- or dibutyl ammonium borates.

An antioxidant may optionally be used, if desired. Typical antioxidantsinclude 2,2-di(4-hydroxyphenyl)propane, phenothiazine, amines such asphenylalphanaphthylamine and hindered phenols such as dibutyl cresol.Generally, the amount of antioxidant used will vary from 0 to about 3%by weight, e.g., from about 0.001 to about 2% by weight based on thetotal weight of the fluid composition.

Additionally, other additives, if desired, may be incorporated into thefluid composition. For example, corrosion inhibitors such as butynedioland rubber swelling adjusters such as dodecyl benzene may be used.

The above-noted inhibitors and additives are merely exemplary and arenot intended as an exclusive listing of the many well-known materialswhich can be added to fluid compositions to obtain various desiredproperties. Other illustrations of additives and diluents which may beused can be found in U.S. Pat. No. 3,377,288, and in Introduction toHydraulic Fluids by Roger E. Hatton, Reinhold Publishing Corp. (1962).

The following examples depict various embodiments of the presentinvention; they are intended to be illustrative and not limiting innature. All parts and percentages are by weight unless otherwisespecified.

EXAMPLE 1 Formation of (C₃ N₃ O₃)[(C₂ H₄ O)₃ CH₃ ]₃

A one liter three neck flask is equipped with a stirrer, refluxcondenser and an adapter, carrying a dropping funnel and a thermometer.Provisions are made to blanket the system with nitrogen during thereaction.

The flask is heated by a mantle, which in turn is connected to atemperature controller.

The reactor is charged with 87.8 g trisodium cyanurate Na₃ (C₃ N₃ O₃)(0.45 moles) and slurried with 300 ml N,N-dimethylformamide (DMF). Thedropping funnel is charged with 249.1 gmonochlorotriethyleneglycolmonomethylether, [Cl(C₂ H₄ O)₃ CH₃ ] 99.0%purity (1.35 moles).

The reaction flask is purged with nitrogen and the thermostat set for64° C. When this temperature is reached, the addition of the chloride isstarted and maintained at such a rate that about 1.5 hours are requiredfor the addition. During this time the pot temperature is allowed torise to 80° C. by periodic readjustment of the temperature controller.After the addition is completed, the pot temperature is set to 130° C.and maintained there for 12 hours, while the reactor is stirred.

The mixture is now cooled, filtered and the NaCl filter cake is washedtwice with about 120 ml DMF each. Filtrate and these washes arecombined.

To check for completion of the reaction, the NaCl filter cake is freedfrom adhering DMF by several diethyl ether washes and then vacuum driedand weighed.

80.5 g NaCl is obtained.

The filtrate is vacuum stripped to remove the DMF. The remaining crudeturbid product is again filtered to yield 219.9 g of clear product.

Molecular distillation at between 10⁻³ and 5×10⁻⁴ mm Hg gives 8.5 gforecut, distilling at an evaporator temperature of 100° C.

At a temperature of 225° C., 155.4 g product is recovered leaving 43.8 gundistilled residue.

The distilled main cut represents a 60.8% yield of product based on Na₃(C₃ N₃ O₃) charged. An analysis of some of the product's physicalcharacteristics is shown in Table I, below.

EXAMPLE 2 Formation of (C₃ N₃ O₃)[(C₂ H₄ O)₄ CH₃ ]₃

Using the experimental set up as in Example 1, 107.3 g Na₃ C₃ N₃ O₃(0.55 moles) in 400 ml DMF, reacted with 391.7 g Cl(C₂ H₄ O)₄ CH₃ (95.5%purity, 1.65 moles) gives after work up, 333.4 g crude product.

The molecular distillation, again carried out between 10⁻³ and 5×10⁻⁴ mmHg, gave a 53.7 g distillate forecut at 150° C. and a 225.5 g main cutdistillate and 44.1 g residue at 275° C.

The main cut product was obtained in 58.2% yield based on Na₃ C₃ N₃ O₃charged. An analysis of some of the product's physical characteristicsis shown in Table I, below.

EXAMPLE 3 Formation of (C₃ H₃ O₃)[(C₂ H₄ O)₂ CH₃ ]₃

With the experimental set up as in Example 1, 87.8 g Na₃ C₃ N₃ O₃ (0.45mole) in 350 ml DMF was reacted with 214.7 g Cl(C₂ H₄ O)₂ CH₃ (91.5%purity, 1.41 moles) resulting in 232.9 g vacuum stripped product.

Repeating this reaction with the same amounts of reactants at 80° C.instead of 135° C. gave a vacuum stripped product weighing only 96.3 g.

A molecular distillation was carried out on a 317.0 g combined sample ofthese two products. Distillation at 140° C. and 5×10⁻⁴ mm Hg gave a 56.4g forecut distillate. The remaining residual was first filtered througha filter aid to remove a slight turbidity and then distilled at 205° C.and 5×10⁻² mm in the molecular distillation system. This yielded a 145.4g main cut product and 16.9 g residue.

The combined yield is 37.9% by weight based on Na₃ C₃ N₃ O₃ charged. Ananalysis of the product's physical characteristics is shown in Table I,below.

COMPARISON 1 Formation of (C₃ N₃ O₃)(C₂ H₄ OC₄ H₉)₃

Using the experimental set up as in Example 1, 136.5 g Na₃ C₃ N₃ O₃ (0.7mole) in 500 ml DMF was reacted with 297.7 g ClC₂ H₄ OC₄ H₉ (2.136moles, 98.8% by weight purity) to give 153.2 g vacuum stripped product.

Molecular distillation at 150° C., 10⁻³ mm Hg followed at 195° C.,5×10⁻² mm Hg yielded a combined distillate main product weighing 142.8g. An analysis of this product's physical characteristics is shown inTable I, below.

                                      TABLE I                                     __________________________________________________________________________    PHYSICAL AND FLAMMABILITY PROPERTIES OF CYANURATE FLUIDS                                        Visc..sup.1                                                                       Visc..sup.1                                                                       Visc..sup.2                                                                       Flash.sup.3                                                                         Pour.sup.4                                Example                                                                            Compounds    100° F.                                                                    210° F.                                                                    Index                                                                             Point (°F.)                                                                  Point (°F.)                        __________________________________________________________________________    C1   (C.sub.3 N.sub.3 O.sub.3) (C.sub.2 H.sub.4 OC.sub.4 H.sub.9).sub.3                         36.75                                                                             4.83                                                                               58 370   -44                                       3    (C.sub.3 N.sub.3 O) [(C.sub.2 H.sub.4 O).sub.2 CH.sub.3 ].sub.3                            58.14                                                                             6.57                                                                               85 345   -27                                       1    (C.sub.3 N.sub.3 O) [(C.sub.2 H.sub.4 O).sub.3 CH.sub.3 ].sub.3                            45.08                                                                             6.58                                                                              107 380   -38                                       2    (C.sub.3 N.sub.3 O) [(C.sub.2 H.sub.4 O).sub.4 CH.sub.3 ].sub.3                            43.58                                                                             7.18                                                                              138 390   -44                                       __________________________________________________________________________                   4 Ball.sup.5                                                                         Wick.sup.6                                                                          Spray.sup.7                                                                          Autoignition.sup.8                                        Wear (mm)                                                                            Test (Cycles)                                                                       Mist. Flam.                                                                          Temperature                                __________________________________________________________________________                   0.78   10    Fire at torch                                                                        709° F.                                            1.17   16    Fire at torch                                                                        721° F.                                            1.02   16    Fire at torch                                                                        730° F.                                            0.71   23    No fire                                                                              736° F.                             __________________________________________________________________________     .sup.1 Viscosity is measured according to test method given in ANSI/ASTM      D44574  Kinematic Viscosity of Transparent and Opaque Liquids.                .sup.2 Viscosity Index is calculated according to the method given in         ANSI/ASTM D227077  Calculating Viscosity Index from Kinematic Viscosity a     100° F. and 210° F. (Appendix 2).                               .sup.3 Flash Point is measured generally according to test method             ANSI/ASTM D324377  Standard Test Method for Flash Point of Aviation           Turbine Fuels by Setaflash Closed Tester (except employed 4 ml of sample      in a high temperature Setaflash instrument).                                  .sup.4 Pour Point is measured according to test method ANSI/ASTM              D9766(1971)  Standard Test Method for Pour Point of Petroleum Oils.           .sup.5 4 Ball Wear is measured according to test method ANSI/ASTM             D226667(1977)  Standard Test Method for Wear Prevention Characteristics o     Lubricating Grease (FourBall Method), employing conditions of 1 hour,         167° F., 1200 rpm and 40 kg load.                                      .sup.6 Wick Test is determined according to U.S. Bureau of Mines Schedule     30.                                                                           .sup.7 Spray Mist Flammability is determined according to ANSI/ASTM           D311975  Standard Test Method for Mist Spray Flammability of Hydraulic        Fluids.                                                                       .sup.8 Autoignition Temperature is determined according to ANSI/ASTM          D215566(1976)  Standard Test Method for Autoignition Temperature of Liqui     Petroleum Products.                                                           For all tests except Viscosity and Pour Point test, one part by weight        antioxidant (phenylalpha-naphthyl-amine) was added to 100 parts of each       product.                                                                 

For all tests except Viscosity and Pour Point test, one part by weightanti-oxidant (phenyl-alpha-naphthylamine) was added to 100 parts of eachproduct.

What is claimed is:
 1. In a method wherein a first mechanical effort isconverted to pressure at a first location, the pressure is transmittedfrom said first location to a second location via a hydraulic fluid, andsaid pressure is converted to a second mechanical effort at said secondlocation; wherein the improvement comprises using as said hydraulicfluid one which comprises an effective amount of a compound having theformula: ##STR5## wherein x is an integer from 2-10; Y is eitherhydrogen or methyl group; and R is a lower alkyl group having from 1-4carbon atoms.
 2. The method of claim 1, wherein x is from 3 to
 5. 3. Themethod of claim 1, wherein Y is hydrogen.
 4. The method of claim 1,wherein R is a methyl group.
 5. The method of claim 1, wherein saidcompound has the formula: ##STR6##
 6. The method of claim 1, whereinsaid compound has the formula: ##STR7##
 7. The method of claim 1,wherein said compound has the formula: ##STR8##
 8. In a method whereinheat is passed from a first heat conductor to a heat transfer fluid at afirst location, the heat is transmitted from said first location to asecond location via said heat transfer fluid, and said heat is passedfrom said heat transfer fluid to a second heat conductor at said secondlocation;wherein the improvement comprises using as said heat transferfluid one which comprises an effective amount of a compound having theformula: ##STR9## wherein x is an integer from 2-10; Y is eitherhydrogen or methyl group; and R is a lower alkyl group having from 1-4carbon atoms.
 9. The method of claim 8, wherein x is from 3 to
 5. 10.The method of claim 8, wherein Y is hydrogen.
 11. The method of claim 8,wherein R is a methyl group.
 12. The method of claim 8, wherein saidcompound has the formula: ##STR10##
 13. The method of claim 8, whereinsaid compound has the formula: ##STR11##
 14. The method of claim 8,wherein said compound has the formula: ##STR12##